Receivers for communications systems today are built using one of a variety of possible receiver principles, where the choice of principle is determined by such factors as cost, power consumption and performance requirements. Each receiver principle has its merits, benefits and drawbacks. In order to counteract the drawbacks of a particular chosen principle, a receiver is usually over-dimensioned in order to fulfill the performance requirements, which is then done at the cost of power consumption and component expense.
In addition to this, demands on receivers with high bandwidth as well as high selectivity push receiver designers to use receiver principles or topologies which exhibit imperfections that need to be handled or compensated, usually by means of extensive signal processing.